Measured-service telephone system



J. WICKS MEASURED SERVICE TELEPHONE SYSTEM Original Filed June 5, 1922 4 Sheets-Sheet 1 May 1, 1928.

J. WICKS W MEASURED SERVICE TELEPHONE SYSTEM May 1, 1928. 1,667,915

J. WICKS MEASURED SERVICE TELEPHONE SYSTEM Original Filed June 5. 1922 4 Sheets-Sheet 3 LEW-- J 01m lnfwks May 1, 1928. 1,667,915

J. WICKS mmsunsn SERVICE TELEPHONE SYSTEM ori inal Fi lunaj.. l922 4 Sheets-Sheet 4 T uen m:-

Patented May 1, 1928.

UNITED STATES 1,667,915 PATENT OFFICE.

JOHN WICKS, 01 OAK PAR-K, ILLINOIEL ASSIGNOR, BY MESNE ASSIGNMENTS, TO AUTO- MATIC EIJFIC'IRXG 111G, O (JEEEQICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

MEASURED-SERVICE TELEPHONE SYSTEM.

Application filed June 3, 1922, Serial No. 565,734. Renewed October 19, 1927.

The present invention relates in general to measured service telephone systems, and more particularly, to automatic measured service systems in which a type of paystation apparatus is provided at each snbscribers station requiring thedeposit of a coin for each successful connection.

In one well known arrangement, the call ing device at the subscribers substation is normally inoperative to control the central oflice switches and it is only by first depositing a. coin that the subscriber enabled to render his sender operative to control the switches in the exchange to set up a connection. Thereafter the coin deposited is either collected or refunded depending upon whether the subscriber called responds or not. It the party called is an oilicial of the telephone company or an operator the coin is refunded in any case.

Certain improvements have been devised in the above mentioned system whereby a. calling subscriber must deposit a coin before making a. call provided he desires a connection with another subscriber, while if he des res a connection with an operator no coin is required to be deposited. A par ticular object of the invention is to provide new. circuits for a type of repeater which is used in such an improved system whereby the coin collecting and refunding operations may be controlled or r the two line. conductors of a calling subscribers line in series instead of over one line conductor to ground which, so far as applicant is aware, has been the practice heretofore.

There are other objects of the invention, which together with those enun'ieratcd above, will be described hereinafter with reierenrc I to the accompanying drawings forming part of this specification.

Referring now to the drim'ings comprisinst Figs. 1-4.. inclusive, there is shown by means of the usual circuit diagran'is, enough of the apparatus involved in the invention to enable it to be readily explained and understood.

Referring now particularly to F 1, the substation A is oi the automatic type having the usual talking instrumentalities and an impulse sender S. Being a measured service substation telephone, there is also provided a well known type of coin collectinn' mechanism which may be of the type shown and described in the U. S. patent to Forsberg No. 1,048,219, granted Nov. 5, 1912. lhe line conductors 11 and 12 extend from the subscribers substation to the ex-. change and, at the latter point, terminate in an individual trunk selecting or. line switch (1. This switch is of the usual rotary type in which the wipers have no normal position, always remaining in engagement with the bank contacts associated with the trunk line last used; and its function is to extend the line, when calling, to an. idle trunk line terminating in a first selectu' switch. One of the trunk lines to which theline switch 0, in common with a plurality of other line switches has access, is shown extending to the first selector E, Fig. 3. The relay equipment in Fig. 2, indicated by the reference character D is a repeater, there being one such repeater inserted in. each first selector trunk. At T is shown a discrin'iinating tone machine Whose function to give a discriminating tone to a. recording operator should one be called by the subscriber, indicative of his status, that is, whether he is entitled to certain toll connections or not.

The first selectors such as E are the first in the series of numericalswitches which may comprise first selectors, second selectors, and connectors, which are used to complete connections between calling and called lines. The selector E, Fig. 3, is a switch of the well known Strowger vertical and rotary type and has access to trunk lines extending' to second selectors such as E and E. The second selector E is similar to the first selector E, as is the second selector E However, the circults of the second selector be similar to the one shown at A, although for convenience the measured service equipment has been omitted.

It is customary in automatic exchanges to provide a special group of second selectors through the medium of which a calling subscriber may connect with the various groups of trunk lines extending to the different opcraters and employees of the telephone com- :3 pany, such for example, as the information ltl tit)

operators, trouble operators, recording operators, or the wire chief. The special second selectors are generally accessible from a certain level intheregular first selectors. In Fig. 3 a trunk line is shown which terminates in a set of bank contacts in a lerel ol" the first selector E and which extends to the second selector E The second selector is one of a group of special second selectors which have access to the groups of trunk lines above referred to. One of these trunk lines is shown in the drawings and terminates in the recording operatofis equipment indicated by the reference character which comprises a group of relays, an induction coil, an answering jack J, and a call signal lamp L.

In order to explain the operation of the circuits in detail it will lirst be assumed that the subscriber at substation A desires to call the recording operator at whose position the jack J appears, itbeing possible to accomplish this connection without depositing a coin as was mentirmed hereinbetore. lhen the receiver is removed at the substation A the line relay 26 ot the individual line switch C is energized over the line conductors it and .12 in series. Relay 2b, upon energizing, at its armature Il-l completes a circuit for the switching relay in series with the motor magnet :27. Another result of the energization-of relay it; is that at armature 253 the test wiper 39 is connected midway between the switching relay and the said motor magnet. The operation of the line switch (l depends upon, whether the trunk line with which its wipers 38-4 0, inclusive, arc in engagement is busy or not. Assuming this trunk line to be busy, there will be a ground potential upon the test contact engaged by the test wiper 39, the switching relay .55 is short circuited and the motor magnet 27. being supplied with direct ground \ia the said test wiper, will operate as a. buzzer to advance the wipers of the switch step by step in searclroli a bank contact set which is associated with an idle trunk line. However. it will be assumed in the present case that when the receiver is removed at sul'istation .t the switch wipers 3840. inclusive, are in cngagement with the bank contacts associated with an idle trunk line. and it will be assumed further. that thistrunk line is the one terminating in bank contacts tin-l7. inelusive. Under these conditions. immediately following the energization of the line 26. and from ground, respectively, and extends them by way of armatures 30 and 32, wipers 38 and 40, trunk conductors -l8 and 50, armaturcs 120 and 12 3, armaturcs 123%! and H2, to the upper and lower windings ol' the line relay 110 of the repeater D.

The line relay 11(1 of the repeater l.) is energized over the two sides of the calling line in series and it its armature 117 completes the circuit oi the slow acting relay ill. The latter relay, upon energizing, at its armature l lt) places ground upon the rclcasc trunl; ,-on luctor til by way of the re tardation coil ill thereby establishing a holding circuit for the line switch (l. which extends by way ot' hank contact 16. lest wiper 3t). armature 31 and its from contact. through the. winding of the switching relay 25, and thence through the winding of thc motor magnet 27 to baflery. It will be understood that this holding circuit is cstab lishcd before the slow acting relay 213 has had time to dccncrgize and serves to maintain the switching relay energized through out the connection. A branch of this hold ing circuit also extends by way of private normal comluctor 2a to the multiplied test contacts in the banks of connccttn' switches which have access to the line of the substzn tion A whereby the .--aid line is protected from intrusion in the usual manner.

It, will be remen'ibercd that ground is supplied to the release trunk conductor 49 through the retardation coil 114. This coil is of very low resistance say of about 2 ohms so that the multiples of the test contact lt accessible to the other linc switrhcs are made busy. Other results of the cncrgizzr tion 01' the slow acting rclay 111 are that at armature 151. a circuit is prepared for the slow acting relay 107. at armature 152 a circuit is completed for the don acting rclay 105, and also for the polarizing winding of the electro-polarizml relay 10b. and at armature .150 a circuit completed for the relay 112 in series with the resistance 199. Relay 1047, upon energizing, at armature 13;) establishes a locking circuit. for itself, at armature 136 places an additional ground upon the release trunk conductor 49, at armature 137 prepares a point in a circuit: for relay 107, and at armature 1 355 opens a. point in the circuit of the upper winding of rclay 108. The elcctro-polarized relay 106 does not i-znergize atthis time. as the current llow in its polarized winding does not attract the armatures, though after oncc bring operated the current flow in the polarizing winding is sulliricnt to maintain its armatures attracted. The relay 111 is cllcrgizcd in series with the l'QHlHl'tlHtft, 199 and opcratrs at armature 15-1; to open a point in a certain shunt circuit which will be later described.

It will be noted that the circuit of the line relay 110 includes the relay ltl.) in series tin;

with it. Relay 109 energizes in series with the line relay 110 and at armature 146 opens a point in the circuit of the relay 113. Another result of the energization of line relay 110 that a bridge closed across conductors 200 and 202 which may be traced follows: trunk conductor 200, armature 143 and its back contact, normally closed springs controlled by arn'iatnre 15:39, through the lower winding of electro-polarized relay 106, through the lower winding of relay 108, trout contact and armature 1 18, normally closed springs controlled by armature 14:2, to conductor 202. Upon the closure of the above circuit the line relay 225 of the first selector E is energized. Upon operating, relay 225 completes the circuit of the slow acting release relay 226 which immediately operates to prepare the operating circuits of the selector E at ari'nature 238, and at armature 237 places ground upon the release trunk conductor 301 tlnrough the resistance 24-0. 'lhitsgrouml extends back over the release trunk conductor 201,.through the resistance 199 in the repeater D to battery. The relay 112 is not short circuited at this time as the resistance 240 is high enough to prevent the relay winding from being shunted.

- Before proceeding further with the explanation attention is called to a shunt circuit around armature 148 and its front contact which, it may be mentioned, are the impulse springs of the repeater D that control the operation of the selector E and succeeding switches. This shunt circuitextends as follows: from armature 148, armature 153 and its front contact, back contact and armature 156, back contact and armature 154;, to front contact of armature 1 18. Contacts 153 and 156 on relays 111 and .118 are closed but,.as the relay 112 is energized, armature 15 1 will be in an attracted position and the shunt. circuit will be opened at this point, it l'ieing clear t'rom this explanation that the shunt circuit will not ii'itert'ere with the operation of the impulse springs represented by armature 118 and its working contact in repeating impulses.

Referring now to the substation A it will be noted that the impulse springs on the calling device S are shunted when no coin is deposited in the paystation apparatus by the resrtance hile this resistance is high enough to allow the line relay 110 to deenergize when the calling device operated, it allows sutlicient current to pass over the line to maintain the relay 109 energized as long as it is in the circuit whether the calling device impulse springs are operated or not. The calling subscriber at substa .ion'A may now operate his calling device in accordance with the two digits which it is necessary to call in order to obtain connection with the recording operator. By the operation of the calling device S a series of interruptions produced in the circuit of the line relay 110 of the repeaterD. Line relay 110 deenergizes a plurality or times in response to such interruptions, each time opening the previously traced circuit ofthe line relay 225 of the first selector E. At the first deenergization of line relay 110 an impulse of current is sent to the slow acting relay 107 which .is energized and maintained energized throughout the impulse series. 107, upon energizing, at armature 1&3 places a direct bridge across the trunk conductors 200 and 202 which does not include the resistance 197, the lower winding of the elec tic-polarized relay 106, nor the lower winding of relay 108. This circuit change brought about in order to reduce the resistance and impedance of the switch control circuits to a minimum during the transmission of impulses. The operation of the armature 14% on relay 107 is without function at the present time.

Proceeding now to the operation ot the first selector E, at each deenergization ot the line relay 225 an impulse of current is sent to the verti 'al magnet 232 in series with the slow acting relay 227. Magnet 232 operates to raise the switch Wipers 255-257, in elusive, step by step until they are placed opposite the level of bank contacts in which are terminated trunk lines leading to the special group of second selectors which have access to trunk lines leading to operators positions. The slow acting relay 227 is energized in series with the vertical magnet and maintains its armature attracted throughout the vertical movement of: the switch. Upon the lirst vertical step of the switch. when the otl' normal springs are shitted, a circuit is completed extending from ground on release trunk conductor 241 1,

armature and its front contact, otl' normal spring 2 1-1 and its working contact, and through the winding of the stepping relay 22 to battery. 'lelay 22S, upon energizing, establishes a locking circuit for itself at armature 247, and at armature 2 18 prepares the circuit of the rotary magnet 231. At the termination of the vertical movement of the switch, the slow acting relay 227 is deenergizcd and the circuit of the rotary magnet 231 completed. hlagnet 2331, upon operat ing, rotates the switch wipers into engage ment with the first set of bank contacts in the selected level and at armature opens the locking circuit of the stepping relay which decnergizcs, opening the circuit of the rotary magnet 231, which deenergizes also. The turther operation of the selector lll depends upon whether or not the trunk line with which the wipers 255-257, inclusive, are now associated is busy. Assuming this to be busy. there will be a ground potential present upon thetest contact engaged by the Relay ill] oil

til)

test wiperQfiti and a circuit will be come pleted' extending from the said grounded test coi'it'act by way of the test wiper 256, armature 2.31 and its back contact, armature 25land its back contact. otl' normal spring Bit and its working contact, and through the winding of the stepping relay 225w to battery. Upon energizing, relay 22S establishes a lockitnr circuit for itsell and completesv the circuit of the rotary magnet 22, This al tcrnate operation oi relay 228 and the rotary magnetiliil will continue until the switch wipers 255.-25T. inclusive, are rotated into engagement with the bank contacts as ociated with an idle trunk li-tta whit-in we will a.-sutne. are the bank ct'iniacts ziiilllill inclusive. this trunl; line is idle. there rill he noground potential present upon iii test contact idl engaged by the test wip r 2:30 and no circuit will be completed for the stepping relay 12H. t'l he switching relay 229 will now be e: erg'ized iii seriesv Will: izi" ste iiping relay 23a as it is Iit)lOIi -jC-t rho-r;

circuited. It may he stated at this poirt that the switching relayfliil is oi such higzih resistance that the stepping relay 22:25 energized in series with it. .hclay 22!), upon operating} disconnects the incoming truulc conductors "Jtltl and 202, from th winditnrs of line relay 225 and extends them by way of itl'hlttttltt;-' Jill and 2:33 wipers 237 and i257. hank contacts 2th) and 26:1. trunk conductors 2G7 and 265). armatures W5 and Paul. to the upper and lower windings ot the llt'tt' iehr" jet) of the second selector i The line relay 280 is immediately energrixcd and operates to complete the circuit oi the slow zlt'tltlii' release relay 2st. 'lhe latter relay, upon energizing, 'nepaiw the operating circuits oi lllt' r'clectol' m ima i at arnnt tore 292 and at armature 2% places eround on I came trunk conductor 2 h tlllfliifllt the resistance 29;) therein i i:il)lifiliil1 f a holditnr circuit for the switch of relay WE) ol' the first selector l l.

This ground also PX- tcnds by way of the release trunk coinluctor 301 through the resi tan e 1H9 inthe r peater T) to battery. but as the resistance 231 is included in this circuit the relay iii. is still maintained energized and the shunt circuit around the impulse rpring s H is held open d at arnmtnre 154.

The ca ling subscrihcr ma. now operate his calling devi e in accordance with the second and linal dip'it in the number of the desired operator thereby prtnlucinga set-mid series oi interruptions in the circuit of the line relay ill) of the repeater l) which are repeated by means of the armature 148 to the line relay 280 of the second selector E The selector E is exactly lilte the selector E and its operation will not be described in detail. lt will suliice to say that the switch eha h is raised step by step until the wipers 31t)312, inclusive, stand opposite the level of bank contacts in which are terminated trunk lines extending to the recording 01)- eratofis position, after which the wiperstare automati-ally rotated in Search of an idle trunk line. Assuming that the trunk line shown in the drawings is the first idle trunk li.ne .the switch wipers will finally he brought to rest in engagement withbank contacts 313M515, inclusive, whereupon the switching relay 284,- will be energized. As a result ot the energization of relay 28 1, the trunk conductors 267 and 269 are disconnccttal from the windings of the line relay 280 and are extended by way of wipers 2310 and 312, bank contacts 313 and 31:3, to the upper and lower windings ot' the double wound relay 32H. ltclay 'El'lt') is therefore energized and completes a circuit for the slow acting relay #521, which. upon energizing, in turn closes the circuit for the lamp signal L and also completes the usual holding circuit tor thc selectors I and E which may be traced as :t'oilow.--:: (lrouud by way of front contact and armature one, through the primary winding ot' the induction coil l, through the resistit'll, hank contact 2314, test wiper 311, armature ZUU and its front contact, where it; joins the holding circuit previously descrined. 'lhe suite-hint;- relays 284 and 22$) are maintained energized and the switches i and la are accordingly held in their operated positions.

The desired cormection has now been established. The recording operator is provided with suitable cord circuits and other apparatus and when she perceives the lighted condition of the lamp If she will answer the call by inserting the answer-ring plug of one oi her cord circuits into the jack J and operate her listening key. In order 1011(5- tcriuine the class of service thatthe calling subscriber is entitled to. after operating the lii-teningg key in the cord circuit, the recording operator will throw the key K. By this operation the secondary of the induction coil 1 is conue ted in bridge of the trunk conductors and the discriminating tone on the release trunk may he heard by the recording operator over a circuit 'which includes the secondary ot the induction coil l. The primary of the induction coil l'- is energized over a circuit which extends as follows: from the discriminating tone machine '1, terminals til and 42, front contact and armature Eli. wiper ill), bank contact 4! release trunk conductor it). through the condenser 51. release trunk conductor 5201. front contact and armature test wiper th test: contact 261. conductor 268. front contact and armature lot). test wiper Jill. test contact til-l. resistance 31th and through the'primary windin; ot the induction coil I to ground by vay ol armature 328 and its front contact. It will he noted that in the above circuit there are two other paths for the current ltlU from the tone machine T to take, one of these paths may be traced from release trunk conductor 4:9through the winding of retardation coil 114-, to ground through armature 136 and its front'i-(mtact: the other path may be traced from, release trunk conductor 201 through the winding of the relay 112 to ground, by way of armature 150 and its front contact. l-lowc er. as these circuits .include the winding of retardation coil 114, and the winding of the relay 112, both of which are of high lllllkiiilllfijfi, the greater part'of the current from the tone machine flows over the previously traced circuit. The class of service to which the calling, subscriber is entitled is determined by the particular tone which is connected to the private normal conductor of his line and which is induced in the secondary of the induction coil I and. is audible to the recording operator. As soon as the recording. operator determines the class of service that the calling subscriber is entitled to she will restore the key K to normal. so as to communicate with the calling subscriber. The recording; operator may now converse with the calling subscriber in order to ascertain his desires. The talking circuit may now be traced over the heavy talking conductors and it will be noted that there is a bridge across the talking circuit in the repeater which includes a winding of the elcctro-polarized relay 106 and the lower winding of the relay 108. The lower winding of the relay 108operates as a retardation coil so that the transmission elliciency of the talking circuit is not materially affected by the above mentioned bridge. From this point on, the operation may take any desired course, depending upon the wants of the subscriber, and will not be described. Disconnection is effected in the usual manner by the hanging up of the receive at substation A. This operation opens the circuit of the relay 110. Relay 110, upon dcenergining, sends an impulse to slow acting relay 107 and at the same time opens the circuit of the slow acting relay 111, with the result that this relay drenergizes an in stant later. Belay 107, upon energizing, at its a rmatnrc 1 1 1 completes a circuit for relay 100. Relay 1100, upon operating, at its armature I122 completes a locking circuit for relay 107, at its armature 121 breaks the iockinp circuit of relay 105, and at armalures 1530 and 123 opens the bridge across the trunk condiwtors 200 and 202, with the result that the relay 320' at the recording operators position is dccnergized followed by the (l energization of the slow acting re ay The switching relays in the selector switchcs E and E" are, therefore, also de energized and these switches restored to their normal. position in the usual and well known manner. telay 100 at its armatures 120 and 12S and their front contacts also connects ground and high potential battery restore.

The operation of the system when the subscriber at substation A desires connection with another subscriber will now be described. It will first be assumed that the subscriber at substation A attempts to make connection with the desired partys line without first depositing a coin at his paystation apparatus. lVhen the receiver is removed at the substation A the operations by which the line of the calling subscriber is extended. through the medium of theline switch C and the repeater D to a first selector E are identical with the operations described in the previous case and will not be repeated. The operation of the selector E wherein theconncction is extended to a second selector likewise already have been described and in this case there is nothing new in the operation except that the wipers 25525T, inclusive, are raised opposite a bank level in whichare terminated trunk lines extending to second selectors of the regular trunking system. The second selector E is a switchv of this class and it will be assumed that the trunk line extending thereto is the first trunk line found to be idle and that the selector E establishes connection with the bank contacts 265267, inclusive. The trunk conductors 200 and 202 will now be extended by the operation of the switching relay 229 by way of wipers 255 and 257, bank contacts 265 and 267, to the upper and lower windings of the line relay 270 of the second selector E Upon energizing, relay 270 closes the circuit of the slow acting release relay 271. Upon attracting its armature 275 relay 271 closes a holding circuit which extends as follows: ground by way of ari'nature 27 5 and its front contact, test contact 266, test wiper 256, to arn'iatnre 251 and its front contact, where the circuit divides, one path extending through the winding of the switching relay 229 and the interrupter relay 228 in series, to battery, and the other path extending by way of release trunk conductor 201 to junction point 195, where it joins the branch extending! from ground and front contact of armature 150 in the repeater IDv It will be observed that the above traced circuit contains no resistance such as resistances 2-10 and 295 and, as a result, relay 112 in repeater D is" practically short circuited. This relaytherefore retracts its armature 1534 and closes the previously described 'shunteircuit around armature 1-18 of the line relay 110 and its front contact, thereby rendering the armature HR inell'ectire to open the-bridge across the trunk conductors 200 and 202 when the relay lid is deenergized. Whenthe calling subscriber ope ates his dial in accordance with thcncxt digitzand produces another serieso! interrupt'ions in 'the liue circuit. the l'(rlllllll deener izalzions of rela)" 1,10 will be oi no effect and it will be apparent that lheselcctoi Fr" cannot be opcratedx The difference in the two classes of second selectors will now be apparent. All the selectors which are required to be used in extending a connection to an operato1"s position or'the-line of an otlicial ofthe telephone company are provided with resistance in their release trunkssimilarto the resistances 240 and- 295. while those switches which are used only in connections to lo all subscribers have theresistance omitted. It follows then. t'hatvwhenever itis'attempted to use a switch of the. latter class,- under the circumstances justdescribed, wherono coin is deposited. the relay corresponding to the relay 112 of the repeater in use will be short circnited and will deenergi-ze to disable the operating circuit extending to theswitch thus preventing further extension of the connection.

The. ope 'ation of the: system in the case where the subscriber at substation A d eposits accoin before calling the desired subscriber will DOWbG described and in this connection the process of collecting the coin at the termination of the conrersation will be briefly described. The first operation on the part ofthe subscriber at substation A' is to deposit a. coin of suitable denomination in the coin collectingmechanism provided for that purpose. This mechanism is well understood and its ope 'atioirneed not be explained in detaih \Vherr the coin is deposited it dc scends past the trigger mechanism which is released by the coin with the result that the polarized magnet l of the coin collecting mechanism is'connected in series with the two line conductors and the high resistance winding of rela 2 and the resistance (l. and the resistance .3 is removed from in shunt of thezin'ipulse springs of the 'alling dciirc S; A coinwma be deposited either before oriafterthe:receircr is removed. in either case the latteraction brings about the operation of'the rotary line switch C whereh theline is extended to an idle first selector switch. Assuming that; theselectori Fig. 8, is the switclrto which connection is e?-;- tended. the operatitmsare the. sameas ha re already beendescribed in tl c preceding connection and will not be repeated. It ma be-stated at; this time. however. that the resistance ofoperating magnet 1, the left hand winding of relay and the resistancei ti. so high that it does not materiallr inter fcrc with the transmission of operating inn ])lll-t 5 or with the talking circuit and it is also so high that when the first interruption occurs in the line circuit the relay 109 in the repeater l) deenergiiccs in the same manner as the line rela i lit].

'lhe calling subscriber may now operate his calling device in accordance with the digits of the nuizibor as igncd to the snbriation A. it being assumed that tl1i:-lincis the one'desircd by the calling subscriber. The selector I will respond to the lil t digit in the same manner as has already been described. In the repeater l) the liirtdeetiergization ol' the relay 1th) in rci-lponse to th operation (13' the calling devic ant-es a circuit to be completedfor the relay ll l. l iela 1123. upon energizing. at armature 15.3 opensthecircuit ol'the relay H2. and at the trout contact of this armature establi hes a hit-king circuit for itself. and at armature li lti opens the shunt: circuit around the impnlslng spring HS and its front contact. 'l'his latter l ration is an e sential feature to be willsidered at this tinzc t'or obviously it permits any of the switches in the exchange to be ope 'aled no matter whether the are prorith ed with resistance in the release trunl: such as the rei-dstance i lor not. ltela t's I and llil therefore constitute means re ponsive to the deposit of the coin for rcmlerine' thc repeater l) operatire to repeat impulses regardles of the type of switches which it is attempted to operate.

In response to the second digit dialled hr the calling subscriber a second H'lci'tor li" will also be operated in the usual manner to the desired level in which are terminated trunk line." leading to connector .\ii('ltt'-'. such as the connector l'l Figv -l. which has access to the line of the sub tation 'lh selector I will then rotate in a well under stood manner to select an idle trnn'i; line' which leads to an idle one of illl t conne t r switches and. wh ch. it will be as umed. is the trunk line comprising condnct r.-: tl itrfit lf. inclnsiic. As this trunk line is idle. th n"- will be no ground potential present upon the test contact am and the .--witching rcla 12H will lie miergixcd n series with the --tcppin'.1' relay 2T3. l nunediately upon the cncrgiz ation of relay 274. the trunk condor-ton Q01 and 2072 w ll be extended by wa t ol' wipers 3'15 and 352. bani: contacts 3:72, and 2353. condin'torsv 53 0 and 115 2. normallr cloecd springs controlled by armatnrcs -l lt' and l ii. to the upper and lower windirw of the lin relay ltll of the connector ll.

The rela ltll is therefore nergized orcr a circuit including the br dge in th epeat l) and operates to complete the circuit of tllt' slow acting rela 402. lhe latter relay energizes to prepare the impnlsiirr. c rcuit;

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llio

, of the connector H at armature 421, and at armature 420 places ground on release trunk conductor 381, thereby establishing aholding circuit for the selector switches E and E.

The calling subscriber at substation A may now operate his calling device for the next. digit of the desired number. By this operation, a. series of interruptions is produced in the circuit oi the relays 109 and 110 in the repeater D. The operation of relay 109 is without function at the present time. By the operation of armature M8 on line relay 110 the interruptions produced by the calling device are repeated to the line relay 401 of the connector H which deenergizes a plurality of timesin response thereto. At the first deenergization, a circuit is completed extending from ground by way of armature 41s and its back contact, armature 421 and its front contact, oii' normal springs 422 and 425, througl'i the winding of the slow acting relay 403, and thence through the winding of the vertical magnet 409 to battery. Thecircuit above traced. is the one over which the first verti -al magnet impulse is transi'nittcd. Upon the first vertical step of the switch shatt. the oil. normal springs are shifted and the remaining impulses to the magnet traverse a new circuitwhich is the same as the one above traced except that it includes the cit norn'ial springs 422 and 4.43 and armature 42a and its front contact on slow acting relay 403 which is now energized. The vertical map net 409 operates to raise the switch shaft rarryiug the wipers 450i52, inclusive, step by step until the said wipers are brought opposite the level of bank contacts corre sponding to the number of interruptions in the digit dialled. The slow acting relay 4:03 is energized in series with the vertical magnet and maintains its armature attracted throughout the vertical movement of the switch, and at the tern'iination thercot decnergizes. thereby transferring the impulsing circuit to the rotary magnet 4.10.

The snbi-zcriber at substation A may now dial the next and tinal digit of the dr..,ircd number. As before, a series of inter-ru n tions is produced in the circuit of the line relay 110 of the repeater l) and th ee are repeated to the line relay of the connector H by means o't armaturc 1-18 and its front :V-ontact At each retraction oi armature flili") on line relay 401 an impulse of current is sent over the toliowii'nr circrit: ground, armature 41S and its back conta arn'iature 421 and its front contact, oil noruial s n'ings 422 and 4-23, armature 4124? and its back contact, back contact and armature t ll, armature i417 and its back contact, and thence through the windii'ig oi the rotary magnet 410 to battery. The rotary magnet 410 operates to rotate the switch c 7 J! siait carryii'ig the switch Wipers into engagement with the set o'fbank contacts associated with the line of the substation A, which, we will assume, are the bank contacts 454F456, inclusive. The 7 slow acting relay 406 is energized in multiple withthe rotarymagnet, and at its armature 533 connects the test wiper i431 to the lower winding of the test relay 405, and at arn'iaiure. 434- short circuits the armature 431 and its back contact on the test relay 405, The latter operation serves to preserve the continuity of the rotary magnet circuit while the switch wipers are being rotated over bank contact sets associated with busy telephone lines.

Assuming that the desired line is busy at the present time, there will be a ground potential present upon the test contact 455 engaged by the test wiper et5l and thetest relay 405 will be energized. Upon operatingrelay 405, at armatin'e 480 establishes a point in its locking circuit which is completed upon the dcenergization of slow acting relay e06, at armature 29 short circuits the upper winding of relay -:t0'T,-at armature opens the circuit tor its upper winding, at armature 431 opens a point in the circuit of the rotary magnet, and at armature ll-32 connects a lead from the busy machine to the lower talking CODClUClOl'. This tone is audible to the calling subscriber who is thus notified that the desired line is busy and he will replace his receiver upon the switch- .hook thereby initiating tlie rclc'asc of the operated switches in a manner which will be described later, l

It will now be assumed that the line oi the substation A is idle when the. wipers -ln2, inclusive, are brought into connection with the bank contacts 5t $56, inclusive. Under these conditions, there will be no ground connected to test contact in?) and no circuit is completed for the lower winding of the test relay 405. Then, upon the deenergization oi the slow acting relay 406, acircuit'is completed OKliiHllHg from ground on release trunk conductor 381. by way of armature 430 and its back contact, normally closed springs cimirollcd by armature 437, through tlicdllJPBl' windingoi the switching relay 4.0T, lmclccont-act and arinature 43a. testwipcr 151, tesagcontact 455, through the winding of the switching relay 4.70. and thence through the winding of the rotary magnet 4-74: to battery. 'llhe above circuit is ineii'ective at the present time for the reason that prior to the dccncrgization oi the slow acting relay 400 a circuit 'ior the upper high resistance winding of relay 205 is completed extending from ground by way of back contact and armature 4-72inthe line switch C, bank contact 456. wiper 4-52, through the upper high resistance winding of relay 405,armature 428 and its back contact, front contact and armature 414-, back contact and armature 435, wiper 450,bank

Winding of relay 103, front contact and armature 130, front contact and armature 120, trunk conductor 48, bank contact 45, wiper 38, front contact and armature 30, lineconductor 11, working con-- tact of coin. controlled spring 8 and the said sawing, through the winding of the polarized magnet 1, through the left hand high resistance winding of relay 2, through resistance 6,the ringer magnets, linc conductor 12. armature 32 and its front contact wiper 40, bank contact 47, conductor 50, armature 123 and its front, contact, and thence to ground by way of armature 131 and its front contact. The relay 103 is energized over this circuit and, at armature 1.28 closes a circuit for the relay 101. Relay 101, upon operating, at armature 127 opens the circuit of the slow acting relay 107, at armature 124 grounds the release trunk conductor 49, and at this same armature also connects the resistance 196 and spark condenser 195 in multiple to ground in the coin collecting circuit to reduce the sparking as is the usual practice. and at armature 125 prepares an interrupted circuit for the upper winding of relay 108. Upon the deenergization of relay 105 which occurs shortly after the energization of relay 100 one ground connection is removed from release trunk conductor 49 at armature 130, and at armature 138 the interrupted circuit for the upper winding of relay 108 is completed. The high voltage current flowing over the previously traced coin collecting circuit from the battery B will immediately cause the re lay 2 at the substationA to operate thereby bridging its low resistance right hand wind- .ing across the circuit shunting its high resistance winding and the high resistance 6. Ordinarily the polarized magnet 1 will respond immediately after the operation of relay 2 and will operate to collect the deposited coin and restore the entire coin collecting mechanism to normal at the same time disconnecting its windings from the line conductors 11 and 12. However, it sometimes happens that the armature of the polarized magnet will stick and the relay 108 is provided to insure the collection of the coin in such case. The interrupter I causes relay 108 to rapidly vibrate its armatures thus intermittently short circuiting the high resistance winding of the relay 103 in the coin collecting circuit with the object of intermittently energizingthe polarized magnet, this operation being ordinarily effective to free the armature in case it should stick. Even with the high resistance lower winding of relay 103 in its circuit the relay 2 at the substation remains operated until the coin is collected. When the coin is collected the polarized magnet 1 disconnects itself from bridge of the line conductors 11 and 12 thereby opening the circuit of the relay 103 which deenergizes to open the circuit of relay 1 104, upon deenergizing, opens the circuit of relay 100 at armature 134, and at armatures 130 and 131 restores certain points in the] coin collecting circuit to normal. The deenergization of relay 100 restores the contacts of repeater D' to normal. The removal of ground from the release trunlrconductor 49 opens the holding circuit of relay 25 in the line switch C. Upondeenergizing, relay 25 restores the circuit of the line switch to normal. In this manner all the apparatus is restored to normal and is ready for another call.

Returning now to the operation of the connector H, it will be assumed. that the calling subscriber at substation A replaces his receiver upon the SVltClkhOOk before the called subscriber at substation A does. By the replacement of the receiver at the calling substation, theline relay 401 is deenergized to open the circuit of slow acting relay 402. After decnergization of relay 401 and before the deenergization of relay 402," an impulse of current is sent to the slow, acting relay 406. Relay 406 operates at its armature 433 to remove ground from the release trunk conductor 381 after the slow acting relay 402 is deei'iergized, in order to enable the previously operated switches to be released, after which the connector is protected from seizure upon the deenergization of thisrelay by ground being connected to the release trunk over the following circuit: ground, armature 438 and its front contact, armature 4-33 and its back contact, armature 437. and its front contact, back contact and armature 430, to-release trunk conductor 381. The relays 404 and 407 do not deenergizc upon thedeenergization of slow acting relay 402 for the reason that their locking circuits are still energized by ground through. armature 415and its front contact on the back bridge relay400. As the release magnet circuit is opened at armature 442 on the switching relay 407 the connector switch is not released. 1

The momentary disconnection of ground from the release trunk conductor 381 causes the selectors E and E to be released in the same manner as before described. The disconnection of ground from the release trunk conductor 381 also opens the locking circuit of the upper winding of relay 106 thereby causing this relay to be deenergized. The decnergization of relay 106 brings about the collection of the coin at the calling substation and the release of the repeater D and the line switch C in thesame manner as has been described.

When the called subscriber at substation its normal position. Thus, the connector it :5 embed to restore to normal hy the last part-y to replace his receiver upon tl e switch-hook.

In the operation of the connector H when eonneetion was first made with the line of the auhstation A. it will he remembered that. the relay 40? ran prevented from energizing to eonneet the ringing: current until the switehing, relay 1-70 in the. line switeh energized to clear the ca led line of attzu'hments. This; provision is made so as to guard against the possihility of the ring outv ofi relay energizing: to disconnect the ringing current. or the line relay "t t l ot the line switch C energizing to extend the lin of the substation A to an idle seleetor.

whieh might occur it the ewitching: relay 407 in the connector H energized he tore the switching relay 470 ot the line switeh C. Attention ia also directed to the fact that the circuit of the release magnet 409 ot the eonneet-or H is not closed until the wipers ot the switeh are dieconneeted by the deenergization of relay 407. Thus, the connector H in releasin cannot interfere with the operation of any of the lines to which it has access.

In case the called suheeriher did not answer it will he neeesaary to refund the deposited coin at the payatation apparatus rather than eolleet it. when the railing: suhseriher replaees his receiver. and thia refunding operatimi will now he rietly era plained. Sinee. the ralled suhser her did not answer neither the polarized relay ltltt nor the relay 104 will he energized. Now when the calling suhseriher hangs up his reeeirer the line. rela of the repeat r l.) deem er zizers' and sends an impulse of current to the slow a ting relay 10? at the same time opening the cireuit of the FlOW aetine" relay 111. The latter relay. upon deenergizilur. completes a eireuit extending "ti-om ground by wa of armature 159. and its hark contact. front eontaet and armature tilt. and through the. winding: of the relay lot) to battery. Upon energizing: relay tot) operates as before deserihed except that in the present case sin e relay 104 is: deenergrized the lead from the hattery B i connected t the lower trunk conductor 50. The current flow from the hatterr l t now o 'ierates the relay 103. the polarized magnet l at the rallingg substation. and the relay l. The polar zed magnet t is aetuated to refund the deposited coin rather than collect it. as the peater l) to normal. The removal on ground from the release trunk conductor til hringra zhont the release ot the line with C in the usual manner.

The deeneraization ot the line rela Itt ot' the repeater l). of collze't, also hrin g's ahout the rel ase ot the connector It and the tirst r-tltt'tfit' l) and tllt Mt'ti'tltl selector li in a manner similar to that already deserihed.

The t'eatnres ot' the inrention having." heen devcrihed and a certained what is considered to he new an des red to ha protert d hjy Letters latent will he pointed out in the appended elaims.

hat I elaim is:

1. 111 a telephone s xstem. a suhstation equipped with a coin hox. two talkine 'on dnetora extending from mid, snlirtation to a central station. means at the central atation tor extending: raid conductors into connection with a e: lled tin". means for St1]')]il \'ill{1 talkingcurrent to aid enl tation. a magnet in said coin hox inoperatire re-ponaire to said talking current. a high voltage hatter i'. and means for onneetine' z-aid high voltage hattery to one (it said talkingundra-tors to actuate said magnet to eolleet coine and for etmneetingr said hia'h voltag hatter to the other of said talking conductors to refund coins deposited to pay tor the extended roune tion.

L. In a telephone syetem. a Salutation pl rided with a win hon. two talking condu tors onnecting said FllliStttllOll with a utral otlire. antoniatie switches in the central ofiiee. a calling; deriee at said $ttltl0l] having. impulse springs hride'ed across said talking! eonduet'ors'. a magnet in shunt of eaid impulse F})1i11{ 1'$. means t'or operating" said alline deriee to control the operation of a eeriea of said switches; to extend a conne'- tion to a ealled line. a high voltage hatter means for applying Ptlitl hatter to one of said talliine' condiwtors to actuate raid mag:- net to eolleet coins deposited in aid eoin hox. and lot-hing" mean for maintaining said high voltage hattery eonneeted to said line until the. coins are eolle-"tml.

3. In a telephone system, suhserihers line tlfi extending to a. central. exchange, a station on each line, measured service equipment at the station on each line, automatic selector switches of two classes, means for operating switches of one class whether a coin deposited in said measured service equipment or not, and means controlled exclusively over a metallic circuit for causing switches of the other class to be opm'ati-ve only it a coin has been deposited in said measured service equipment.

t. In a telephone system. subscribers lines extending to a central exchange, a station on each line, measured service equipment at the station on each line, automatic selector switches of two classes, means for operating switches of one class whether a coin is deposited in. said measured service equipn'ici'it or not, and means controlled exclusively over a metallic circuit normally preventing the operation of switches of the other class.

5. In a telephone system. a line extending to a. central exchange and havingcall charging equipment associated therewith, serially related automatic switches at the exchange, a repeater interposed between said line and switches, a control circuit extending from said repeater to one of said switches and including interrupter contacts for controlling the same to operate said switch, a shunt path around said contacts, and a relay in said repeater energized solely over a. metallic circuit including said line to render said shunt circuit effectiveto shunt said contacts, another relay in said repeater 't'or rendering said first relay incllectivc, and means including said call charging equipment for rendering said last relay cliietrtive.

6. In a telephone system, a line extending to a central exchange, coin collecting mechanism at the station on said line, serially related automatic switches at the exchange, a repeater interposedbetween said line and switches, a control circuit extending from said repeal er to one of said switches and including interrupter (fOlltiICt'E-l for controlling the same to operate said switch, a shunt path around said contacts, a relay in said repeater energized solely over a metallic circuit including said line to render said shunt circuit effective to shunt said contacts, and

means controlled over a complete metallic circuit including said line by the depositing of a coin in said mechanism for deenergizing said relay to render said shunt circuit ineffective,

7. In a telephone system, a line extending to a central exchange, coin collecting mechanism at the station on said line, automatic selector switches at the exchange, means "for previaiting said switches from being operated over said line, and means controlled over a metallic circuit completed by the deosit of a coin in said mechanism for render- 1ng sald preventing means ineffective.

8. In a telephone system, a line extending to a central exchange, coin collecting mechanism at the station on said line, serially related automatic switches at the exchange, a repeater interposed between said line and switches, a control circuit extending from said repeater to one ofsaid switches and including interrupter contacts for controlling the same to operate said switch, a shunt path around said contacts, a relay in said re pcater adapted to open said shunt circuit, and means controlled over a complete 1netallic circuit including said line by the depositing of a coin in said mechanism for energizing said relay.

9. In a telephone system, a line extending to a central station, coin collecting mechanism at the station on said line, serially related automatic switches at the central station of two classes, a calling device at the station on said line having impulse springs across the conductin's of said line, a resistance .in shunt of said springs. means for preventing the operation of switches of one class with said shunt across said springs, and means controlled by the depositing oi acoin in said meclnlnism to remove sa,id

shunt to enable switches of either class to be operated.

10. In a telephone system, a line extending to a central exchange, serially related automatic switches atthe exchange, a repeater interposed between said line and switches, a control. circuit extending from said repeater to one of said switches and including interrupter contacts for controlling the same to operate said switch, a shunt path around said contacts and a relay controlled over a metallic circuit including said line for determining whether the said shunt will be eflective or not.

ll. In a telephone system, a line cxtcuding to a central exchange, serially related automatic switches at the exchange, a repcater interposed between the line and said switches, a switch control circuit extending from said repeater to one of said switches, means actuated following the seizure of said repeater to disable said control. circuits, and means in said repeater operable over a full metallic circuit extending oversaid line for causing said switch control circuit to be made efiective.

12. In a telephone system, a line extending to a central exchange, serially related automatic switches of the exchange, a repeater interposed between said line and switches, a control circuit extending from said repeater to one of said switches and including interrupter contacts for controlling the same to operate said switch, a shuntpath around said contacts, and means controlled over a metallic circuit including said line for re moving said shunt.

13. In a telephone system, a line extend lllll llll ing to a central exchange, a circuit including the two sides of said line aid a relay in series with a source of current. a ewitch control circuit including impulse contacts on said relay. and means at the exchange controllahle eye a full metallic circuit, including said line for maintaining said switch control circuit ineti'eetire.

it. In a telephone system. a line extending to a central exchange. an automatic switch at the exchange. a repeater interposed bet ween aid line and switch. a cot'ttrol circuit extending from said repeater to said switch and including; interrupter contacts for controlling the same to operate r-lllltl switch. a shunt path ahout said interrupter contacts. a relay for contrt'illing aid shunt path. and means controlled ove' a metallic circuit including said line for ca :sing the operation oi said last relay.

15. In a telephone system. a line extending to a central exchange. an automatic switch'at the exchange. a repeater interposed between said line and switch. a control circuit extending from said rep :tter to said switch and inclut'ling interrupter contacts l'or controlling the same to operate said switch. a shunt path about said interrupter contacts. a relay for controlling said shunt path. and means controlled over a metallic circuit including said line for preventing! the operation of said last, relay.

16. In a telephone system. a line extend ing to a central exchange, an automatic switel at the exchange. a repeater interposed between said line and switch. a control circuit extending from said rep .ater to said switch and including interrupter contacts tor controlling the same to operate said switch, a shunt path about said interrupter contacts. a relay for controlling said shunt path and ltltiHS controlled ore' a metallic circuit; including said line for 'ausing the operation of said last relay in case the resistance of said metallic circuit, is *aried.

17. In a telephone system, a line extending to a central exchange. an automatic switch at the exchange. a repeater interposed between said line and switch. a control circuit extending from said repeater to said switch and including interrupter conta ts for controlling the same to operate said sw tch. a shunt path about said interrupter contacts. a relay for contrt'illing sa d shunt path and means controlled over a metallic circuit including said line for matting the operation ot said last t'(ltt in ca e the re s stance ot' said metallic circuit is ittci :t-t' l.

In. In a telephone H YHtQlll. a su 'scrihers' inc extending to a central exchange. a staioa n said line. automatic selector writchea :l' two classes. means t'or operating switclie.--: o t' one class. and means: controlled exclu ively over a metallic circuit including said line for preventing the operation of switches of the other class.

19. In a telephone system. a line ext nding to a central exchange. serially related auto matic .-=\\itche.-= at the exchange. a repeater interposed between r-ilitl line and raritchea. a control circuit extending from said t'c,- peater to one of tll l switches and including interrupter contacts for controlling the same to operate rit tl switch. a shunt path around raid contacts. and a relay in said repeater energivcd solely over a metallic circuit including said line to render said hunt circuit eti'cctive to shunt said contacts.

2t]. In a telephone system. a line extcndim. to a central exchange. an automatic swi ch at the exchange. a repeater interpo.---d hetween s'aid line and switch. a switch control circuit extending from said repeater and in cluding a pair of impulse contact a shunt. path ahout Paid impulse contacts includ ng two pairs of normally closed cot'ttactr-= connccted in series. and marginal means in said repeater for opening either contact pair.

In witness whereof. I hereunto suhscrihc my name this 29th day of May, A. l) 102:5.

J OHN W It dirt. 

